The present invention is concerned with a method of generating a computer program for control of an apparatus capable to ablate corneal tissue or a contact lens for treatment of presbyopia.
Presbyopia is the lack of capability of the eye lens to accommodate for far distance and near distance.
The prior art knows many optical approaches to presbyopia including reading glasses, monovision, multifocal contact lenses, intraocular implants, and accommodative intraocular lenses. None of these attempts can restore accommodation but all represent compromises to establish a more or less fair near vision at the costs of far vision. Some methods were designed to restore accommodation by means of scleral expansion near the ciliary body, however, have so far failed to prove efficacy.
In refractive laser surgery, first “presbyopia corrections” have been reported in the early nineties (Moreira H, Garbus J J, Fasano A, Clapham L M, Mc Donnell P J; Multiffical Corneal Topographic Changes with Excimer Laser photorefractive Keratectomy; Arch Ophthalmol 1992; 100: 994-999; Anschütz T, Laser Correction for Hyperopia and Presbyopia, Int Ophthalmol Clin 1994; 34: 105-135). However, such techniques have not gained wide clinical acceptance. More sophisticated presbyopia correction profiles have been proposed including an induced central steep island (CSI), U.S. Pat. No. 5,533,997 (Ruiz) and WO93/25166 (King, Klopotek). The present invention partially refers to the concept of CSI disclosed in the afore-mentioned patents. Also decentered steep areas have been proposed, see U.S. Pat. No. 5,314,422 to Nizzola, and Bauerberg J M, Centered vs. Inferior off-center Ablation to Correct Hyperopia and Presbyopia, J Refract Surg 1999. The prior art also suggests a near vision zone in the mid-periphery of the cornea, see Telandro A, Pseudo-accommodative Cornea: a new Concept for Correction of Presbyopia, J Refract Surg 2004; 20:S714-S717; and Cantu R, Rosales M A, Tepichin E, Curioca A, Montes V, Bonilla J; Advanced Surface Ablation for Presbyopia using the Nick EC-5000 Laser, J Refract Surg 2004, 20: S711-S713.